Cassette for pumping a treatment solution through a dialyzer

Abstract

A cassette is provided for installation in a dialysis monitor to pump a treatment solution through a dialyzer. The cassette is a unitary component with a hydraulic manifold (53) and a pneumatic manifold (54) integrated into a body (52). The body (52) has connectors for connecting the hydraulic manifold (53) to the dialyzer and the pneumatic manifold (54) to a pneumatic pressure source. A set of solution pumps is integrated in the cassette, and each solution pump includes a pump cavity inside the body. The solution pumps are operable to displace the treatment solution through the hydraulic manifold (53) to and / or from the dialyzer by action of a reciprocating gas-liquid interface in the pump cavity (30) of the respective solution pump. The gas-liquid interface is formed directly between a gaseous substance and the treatment solution. A valve arrangement (58) is attached to the body (52) and operable to control admission of the gaseous substance and the treatment solution to the pump cavity (30) so as to reciprocate the gas-liquid interface and thereby pump the treatment solution through the hydraulic manifold (53). The cassette is configured to pump the treatment solution without moving parts inside the body (52).

Description

TECHNICAL FIELD[0001]The present invention generally relates to the field of renal replacement therapy by the use of a dialysis system for extracorporeal blood processing, and in particular to a cassette for pumping a treatment solution through a dialyzer in such a dialysis system.BACKGROUND ART[0002]In extracorporeal blood processing, blood is taken out of a human or animal subject, processed in a dialyzer and then reintroduced into the subject by means of an extracorporeal blood flow circuit. Such extracorporeal blood processing includes hemodialysis, hemodiafiltration, hemofiltration, ultrafiltration (fluid removal), etc.[0003]Generally, the extracorporeal blood processing is aimed at achieving movement of water and solutes across a semi-permeable membrane inside the dialyzer. In many types of extracorporeal processing, this is achieved by pumping the blood through the dialyzer on one side of the semi-permeable membrane and by pumping a treatment solution (dialysis fluid) through...

AI Technical Summary

Benefits of technology

The technical effect of this patent is to improve the reliability and prevent operational failure and leakage in a dialysis system's supply arrangement for treatment solution. This is achieved by using solution pumps with a gas-liquid interface, which can remove gases, such as air, from the liquid. The pumps have an inherent gas removal function, which can be enhanced by a valve arrangement that creates a negative pressure in the pump cavity during operation. This helps to ensure proper operation of the solution pumps and dialyzer.

Problems solved by technology

The manufacturing of such a supply arrangement is labor intensive.

Also large number of connections and detachable and movable parts may lead to leakage of fluid and / or operational failure and need for maintenance.

Thus, manufacture is complex and the supply arrangement has many points of failure as well as many connections that may cause leakage.

It is realized that a failure in a moving component inside one of the cassettes results in rejection of the entire cassette, or even the entire cassette system, since it may be difficult or impossible to open the cassette to replace the failing component.

Furthermore, the provision of plural membranes inside the cassette constrains the design of the cassettes and may result in an increased form factor.

Even if fluidic pumping systems are known as such, the prior art does not suggest the use of these fluidic pumping systems in medical systems in general, let alone for pumping of treatment solution in dialysis systems.

Nor does the prior art suggest that these fluidic pumping systems could be integrated in cassettes or bonded manifolds.

This results in a compact design of the cassette.

The valves, which contain moving parts, may be the most likely point of failure during operation of the cassette for a prolonged period of time.

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